Integrated Fuel Injector Cooling for Attritable Engine Inspection

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Solution Overview

Problem

Attritable aircraft engines face challenges with complex and heavy fluid dispensing systems that are costly, difficult to maintain, and require numerous parts, which complicate manufacturing, packaging, and inspection.

Innovation Solution

An additively manufactured attritable engine with integrated cooling holes allows for each injector to be individually tested by inducing a phase change in a flow test fluid, using cooling fluid to block other injectors, enabling faster and less expensive inspection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fluid dispensing systems are used in attritable engines, then reliability is improved through multiple parts and redundancy, but device complexity increases with more than 30 individual parts requiring assembly

Engineering Contradiction:

Improvesystem reliabilityVSAvoidnumber of parts

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the fuel dispensing system into a single monolithic structure formed by additive manufacturing. The fuel rail, injectors, and cooling channels are integrated into one component, eliminating the need for multiple separate parts and complex assembly processes while maintaining system functionality and reliability

Inventive Principle:

Principle #5Merging (Combining)

2Strength

If conventional fuel rails with multiple parts are used, then manufacturing robustness is improved, but manufacturing time and costs increase due to brazing more than 10 individual parts

Engineering Contradiction:

Improvemanufacturing robustnessVSAvoidmanufacturing time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The patent replaces traditional mechanical assembly processes (brazing, welding, fastening) with additive manufacturing technology. The monolithic fuel dispensing system is built layer-by-layer through 3D printing, eliminating the need for time-consuming joining operations while maintaining structural integrity and strength

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If conventional fluid dispensing devices are used, then functional capability is improved through multiple operating parts, but weight increases making them heavy and difficult to package

Engineering Contradiction:

Improvefunctional capabilityVSAvoiddevice weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent combines multiple functional components (fuel rail, injectors, cooling channels) into a single integrated monolithic structure. This consolidation reduces the overall device weight while preserving all necessary functional capabilities through the additive manufacturing process that creates internal cooling channels and injector passages within the single component

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If conventional fuel dispensing systems with more than 30 parts are used, then functional redundancy is improved, but ease of manufacture deteriorates due to complex assembly requirements

Engineering Contradiction:

Improvefunctional redundancyVSAvoidassembly complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces complex mechanical assembly processes with additive manufacturing. The monolithic fuel dispensing system is created through 3D printing technology that builds the entire structure including internal passages and cooling channels in a single manufacturing process, eliminating the need for assembling multiple separate parts

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution simplifies manufacturing, reduces costs, and facilitates rapid, cost-effective inspection of individual injectors, ensuring compliance with stringent flow requirements.

Implementation Method 1

The engine case wall includes at least one second cavity embedded within the engine case wall and defines at least one cooling channel that is in thermal communication through the engine case wall with the injector

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

injecting a cooling fluid into an at least one cooling hole for each of (N−1) injectors and inducing a phase change to a flow test fluid in each of (N−1) injectors, which prevents flow through each of (N−1) injectors

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS12480658B2Cooling fuel injector system for an attritable engine

Publication Date: 2025.11.25 RTX CORP

AI summary

An additively manufactured attritable engine includes a compressor section, a combustion section, a turbine section, and an engine case wall, which surrounds the compressor section, the combustion section, and the turbine section. The engine case wall includes a first cavity embedded in the engine case wall that defines an injector that is in fluid communication with the combustion section. The engine case wall includes at least one second cavity embedded within the engine case wall and defines at least one cooling channel that is in thermal communication through the engine case wall with the injector.